ABSTRACT
The aim of this preliminary study was to examine the developing cognitive profiles of children with cerebellar tumours in a consecutive series of clinical patients. MRI and longitudinal intellectual profiles were obtained on seven children (two females, five males; mean age 3 years at diagnosis; mean age 7 years at first assessment). Tumours in three of the children were astrocytomas; of the remaining tumours, two were medulloblastomas, one low-grade glioma, and one ependymoma. In right-handed children, we observed an association between greater damage to right cerebellar structures and a plateauing in verbal and/or literacy skills. In contrast, greater damage to left cerebellar structures was associated with delayed or impaired non-verbal/spatial skills. Long-term cognitive development of the children studied tentatively supports a role for the cerebellum in learning/development. These findings suggest that lateralized cerebellar damage may selectively impair the development of cognitive functions subserved by the contralateral cerebral hemisphere and, in addition, that all children with cerebellar lesions in early childhood should routinely undergo long-term monitoring of their intellectual development.
Subject(s)
Cerebellar Neoplasms/complications , Cerebellar Neoplasms/physiopathology , Cognition Disorders/etiology , Cognition Disorders/physiopathology , Functional Laterality/physiology , Glioma/complications , Glioma/physiopathology , Cerebellar Neoplasms/pathology , Cerebellum/pathology , Cerebellum/physiopathology , Child , Child Development/physiology , Child, Preschool , Cognition Disorders/pathology , Dyslexia/etiology , Dyslexia/pathology , Dyslexia/physiopathology , Female , Glioma/pathology , Humans , Intelligence Tests , Male , Memory Disorders/etiology , Memory Disorders/pathology , Memory Disorders/physiopathology , Neuronal Plasticity/physiology , Neuropsychological Tests , Speech Disorders/etiology , Speech Disorders/pathology , Speech Disorders/physiopathologyABSTRACT
Developmental dyslexia is a disability of literacy skill that has also been associated with sensory processing deficits, primarily for the detection of dynamic auditory and visual stimuli. Here we examined whether analogous deficits extend into the domain of somatosensory perception. Detection thresholds for each of three frequencies of vibration were obtained for 11 readers with a prior history of dyslexia and 14 similarly aged adult controls. The poor readers were significantly less sensitive to vibration at 3 Hz (P<0. 01) but not at either 30 or 100 Hz. Detection of each of these three vibration rates is mediated primarily by a separate somatosensory fiber tract; deficits selective to 3 Hz therefore suggest an impairment within the slow-adapting I (SAI) fiber system beginning with Merkel-cell mechanoreceptors in the glabrous skin. Such evidence is compatible with the hypothesis of a generalized, multisensory deficit of temporal processing functions in dyslexia.
